# Examples for 8th grade - page 3

- Reverse Pythagorean theorem

Given are lengths of the sides of the triangles. Decide which one is rectangular: Δ ABC: 73 m, 66 m, 51 m ? Δ DEF: 63 cm, 105 cm, 84 cm ? Δ GHI: 50 dm, 48 dm, 14 dm ? Δ JKL: 31 m, 45 m, 40 m ? Δ MNO: 28 m, 53 m, 45 m ? - Proof PT

Can you easy prove Pythagoras theorem using Euclidean theorems? If so, do it. - Root

The root of the equation ? is: ? - Troops

Route is long 203 km and the first day first regiment went at an average speed 20 km/h and journey back 19 km/h. The second day went second regiment same route at an average speed 18 km/h there and back. Which regiment will take route longer? - Flags

How many different flags can be made from colors red, white, blue, black, yellow, green, purple, gray, orange so that each flag consisted of three different colors? - Triangle

Can be rectangular triangle equilateral? - Above 100%

What is 155% of 210? - Guests

How many ways can 7 guests sit down on 9 seats standing in a row? - Stock market

Simon one day decided to invest € 88000 to the stock market. After six months he invested July 5 stock markets fell by 56%. Fortunately for Simon from July 5 5 to October 5 his shares have risen by 39%. Simon is then: ? - Height

Is right that in any right triangle height is less or equal half of the hypotenuse? - Logs

Trunk diameter is 72 cm. Is it possible to inscribe a square prism with side 54 cm? - Playing cards

How many possible ways are to shuffle 7 playing cards? - Series

Andrew wrote this series of numbers: 1,3,7,15, .... n. Which number in the series does not belong? ? - Shelf

How many ways are there to arrange 9 books on a shelf? - Ace

From complete sets of playing cards (32 cards) we pulled out one card. What is the probability of pulling the ace? - Logic

A man drinks a barrel of water for 31 days, woman for 58 days, for how many days they drink barrel together? - Percent calculation

Calculate 72% if 96% is 93. - Trapezoid

Are diagonals in a rectangular trapezoid perpendicular and bisect the angles? - Road

Between cities A and B is route 3 km long of rise average 4‰. Calculate the height difference of cities A and B. - Painter Pavel

Painter Pavel painted the fence for 20 hours and painter Petr the same fence painted for 17 h. How long should take painted the fence together?

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